Carbureter for internal-combustion engines.



0. 1 LI] OAS. GABBURETEB. FOR IN'IERNAL COMBUSTION ENGINES. APPLICATIONFILED JUNE 3, 1913.

1,082,466, v g: Patented Dec.23,i913.

m TNESSEJ.

vented certain new and useful nmrnn snares. PATENT mm;

OWEN DAVID LUGAS, F BAYSWATER, 130m, BHG'LAH D.

' .cmnnnrns, non mrnnmincomane'rron ENGI ES.

Specification of'l'iefiers latent.

Patented;Dec.23,1 913.

Application filed June 3, 1913. serialll'o. 771,471.

To all whomit may concern Be it known that I, Owen DAVID LUCAS, asubject of His Majesty the King of England, residing at Bayswater, inthe county of London, Kingdom of England, have in- Improve meats inCarburetors for I'nternalQombustion Engines, of which the following a.

specification.-

This invention has reference to improve ments in carburetors forinternal combustion engines, and its object is to provide a more perfectmixture under all conditions of engine load and speed than hasheretofore been attained.

The invention-has to do particularly with that type of carburetordescribed in my application filed on March 18, 1911, Serial No.

615,29 t, wherein there is provided a jet sitnoted in a jet .chamber, asdistinguished from the mixing chamber proper, the jet chambercommunicating w th the mixing chamber by suitable orifices. In the corbureter of theaforesaid application the mixing chamber is exposed to thedirect suction of the engine, there being no throttling means betweenthe mixing chamber and en gine, while the air snpply'is controlled by 'amechanically ariable port between the.

mixing chamber and the atmosphere. The

i suction on thejet, and consequently the amount of hydrocarbon admittedto the mixing chamber. is in the structure shown. in the aforesaidapplication controlled by a mechanically variable port between the jetchamber and the atmosphere, the arrangement being such that if theeffective area of the air po i t to the. mixing chamber is beingincreased, that'of the air port of the jetchamber is beingcorrespondingly diminished, and vice versa.

According to the presentinvention means are-provided for \controlhngthesuction of the jet by -mechanica lly vary ng the size of the orificethrough which communication is had between the jet and mixing chambersand the arrangement isalso, such that whe the effective area of the airport of the mixing'chamber is bemg enlarg the orific between lzhejet andmixing chambers is in- 50 creased in effective area, and vice versa,while the port between the jet chamber and the atmosphere remainsconstant, Again, the variable orifice between the jetand mixing chambersmay be employed in a carburcter Where the-air portsof the jet and micederstanding that while the drawings show a practical form of the.invention, the latter is not confined to any strict conformity with theshowing of the drawings but may be changed and modified so long as suchchanges and modifications mark no material departure from the salientfeatuics of the invention.

' In the (l1-a\vings:---Figure l isa diagram illustrating the invent-ionin its simplest adaptation. Fig. 2 is a similar diagram illustrating theinvention as embodied in 1 I carbureter operating according to theaforesaid application. j

Referring to the drawings there is shown a carburetor provided with amixing or secondary-air chamber a coimnunicating with the -atmosphere byan air port '0 and with the cylinder is of an engine by aninduction pipe1'. There is, also provided a jet or pr1mary-air chamber-d entered atthe lower portion by a jet j which may be considered as fed by aconstant level'float feed device such as'colnmonly employed incarbureters. The chamber 1 communicates directly with the atn'iospherebyway of .a port e lo ated at a pointdistant from the i t The port 0iswntrol d-e tear chambers.

- the suction of thejet is by a throttle-f which is'simply'indicated asa sliding throttle and may be arranged to either control the port 0alone, as in Fig. 1 5 or to simultaneously and oppositelvcontroii. theports-c and e, as in Fig. 2. echam -v 'bers a and d communicate throughan orifice. l, which may be either singleor multiple, it being,sometimes advisable to, have the orifice Z composed of a'number of smallpassages, but in any. event the area of the orifice 1, whether singleorrmultiple, is small or minute as compared with the ports e and 0, andparticularly the port a. In the structure shown in the aforesaidapplication this orifice: is of constant area at all times, while thecontrol of the suction of the jet is afiected by a manipulation of thethrottle common to the air ports oj both the. jet and In accordance withtheresent invention rther controlled by a shutter o adapted-to .vary theefiective area of the orifice 1 between the two cham bers d and e and soarranged that when the port a isincrea'sed or diminished in effectivearea the orifice I will be varied in efiective area in the same sense asthe port a. In Fig. l. the'port e remains constant durin the adjustmentsof the port a and orifice In. Fig. 2 the port 0 and orifice Z-areincreased or diminished in efiective area in the same sense,'while theport 6 is diminished in effective area as t e port 0 and orifice] areincreased in effective area, and is increased 'in effective area as theport a and orifice l are diminishedin effectivearea. The move- .ments'of the two control shutters f and 0 may be caused in any suitablemanner, and this may be brought about by any suitable bperatingmeans,such as indicated in the drawings, where there is shown a bell-cranklever g, pivoted at h and connected ,bylinks a, z", to .the shutters or--valves f and a, respectively. 'An'operating link a connected to thelever 9 may extend to any convenient point. I

When the engine piston is moving on the suction stroke, subatmosphericconditions are produced within the chamber a and simi? lar conditionsare also produced in the chamber (1, since these two chambers are.in'communication by: way of the orifice l,

v and while both chambers may. each be in communication with the atmosherethrough the respective air ports,c an e there are still suchsubatmospheric' conditions in, the chamber-d that there is caused'an.inflow of fuel through'ithejet' j and this is -met,by air, which'may betermed primary air, en-

teringtherhambertlthrough the air port-e and vthe-primary: air and .fuelpass into the mambem amugh the oricel which isof eitl've area here thediluting ort c is met and a suita le mixture is efected. Theair port ofthe chamber a is ;.so situated that when it is decreased in effcetivearea 'thedegree of subatmospheric pressure in the chamber a caused bythe suction of the .engine tends to increase, wherefore a similarcondition arises in the chamberd in the structure shown in Fig. 1 andthis'condition may be increased or diminished by varying the effectivearea of the orifice l. In the structure shown in Fig. 2 'the air port ofthe jet or primary air chamber decreased in efiective area as the airport-to the chamber a is increased and .vice .versa, and while adecrease of the effective sizeof the air port 0 tends to increase thesuction at the jet 7' this tendency is to an extent counteracted by thesimultaneous opening oi the port e, which under these circumstancesbecomes a jet. controlling port. The action of the air ports and itsthrottle on the jet is opposite to the manner in which a throttleoperates when it is laced, as is customary, in the suction pipe etweenthe jet and the engine.

The action of the jet is modified by increasing or diminishing theeffective area ofthe orifice Z and increasingor diminishing of theefi'e'ctive area of the air port 0 both in thesame sense, and under somecircumstances the action is further modified by the decrease orenlargement of the effective area of the port e with the increase ordecrease of the elfective area of the port a, this is in the oppositesense thereto.

What 'is claimed is 1. A carbureter, for internal combustion engines,provided with two separate chambers, one chamber having means forfreeconstant communication with the engine and also provided with an airport opening directly to the atmosphere, and the other chamber havingan' air ort opening directly to the atmosphere and also having a 'fuelinlet in the lower portion'thereof, said chambers being in directcommunication through 'a small orifice located on substantially thelevel of the mouth of the jet, and said orifice and the air port of thefirst-'namedchamber bein provided with throttling means for regu atin'gtheir efiective areas and movable in the same sense. 2. A carburetor,for internal combustion engines, provided with two separate cham bers,one chamber having means for free constant communication with the engineand also provided with an air nbrt opening chamber havin an airportopeningjdirectly to the atmosp ere and also havin a fuel inlet inthe lower portion thereof, said chambers being-in directcommunicationthrough or secondary air enterin 'by way of the i directly to theatmosphere, and the' other a small orifice located on substantially thethe opposite sense to the movements of the level of the mouth of thejet, and said orifirst-named throttling means. 10 fice and the air portof the first-named In testimonywhereof I have signed this chamber beingprovided with throttling specification this 21st da of Mayl9l3. 5 meansfor regulating their effective areas OWEN AVID LUCAS.

and movable in the same sense, the air port Witnesses: v of thesecond-named chamber being also JNo. D. ELKIN, provided with throttlingmeans movable in GEORGE I. Bnmens.

